Automotive Type-C Charging Trends and Challenges

Automotive USB Type-C Charging Trends and Challenges. In this training, we will briefly introduce current and future automotive USB charging scenarios and go into details of automotive USB charging with the new-generation fully integrated USB Type-C device of TPS25830 and TPS25831. We will go over roadmap devices, system design considerations for automotive USB charging in head unit, media hub, rear seat charger, and local A port.
What we will learn from this training is to understand the trends of automotive USB charging scenarios and learn how to design automotive USB charging with TPS25830 and TPS25831. The level of this training is intermediate and focusing on analog band systems.
First, let's look at automotive USB ports today and in the future. USB standard has been upgrading itself from data side and power side, also the front of the connector. We are today at the transition from Type A connector to Type C connector in automotive. The power that a USB port could provide also increasing from 5.0 at 1.5A that applies to be BC 1.2 to Type-C 5-volt at 3A, and even 20-volt at 5A with power delivery.
Here is a typical automotive USB system for a 2021 car and beyond. This shows how the USB port have been set up in cars. We could have one or two USB ports in the head unit. Which one of them connects to the media hub via an internal cable to further extension? Some cars may even extend ports to the back seat.
These modules are connected via internal cables. The internal cable between HUB unit and media hub normally has both USB power and data lines, so that the data can come through a media USB port to the head unit. While the internal table between media hub and the USB back seat charger may only have the power lines, because in most cases, there is no data communication required by the back seat.
A USB charging port controller, or power delivery controller, are required for each USB port that expect to fast-charge the device. And in the middle, there is a 5-volt available or not in the system. It is recommended to have a DC/DC for USB port in case of any short circuit at the USB port that could impact the other function in the system.
So DC/DC and the USB controller are basic components for a USB charging port. We can see that in the system [INAUDIBLE] diagram of automotive USB charging, a wide [INAUDIBLE] DC/DC converter is needed to convert battery voltage to 5-volt for VBUS.
A USB power switch is needed to protect VBUS from shock and overload. A USB charging controller is needed to do handshake with the device following BC 1.2, or Type-C, or PD standard. All USB [INAUDIBLE] requires system-level ESD protection and some OEMs, even with prior short-to-12-volt-battery protection.
In TI, we have solutions for all these functions both descriptively for flexibility and all in one device for easy to use. We will focus on the roadmap devices of TPS25830 and TPS25831 in this presentation, which are all-in-one devices with all the functions integrated in the yellow circle.
So let's see system design with the TPS25830 and TPS25831. For a USB port in the head unit, the customer cares about fast charging and data communication for applications like carplay, [INAUDIBLE] auto, et cetera. TPS25830 has integrated Type-C and BC 1.2 CDP mode to support Type-C faster charging and data communication.
Cable compensation is also very important in head unit. As the USB connector normally located remotely from head unit is connected via internal cable, which will introduce VBUS droop and the lower the charging power. TPS25830 has a cable compensation feature to dynamically composite the VBUS droop, so that the remote VBUS remains viable over time.
The internal cable also introduced big impact on the eye pattern of the USB. Though eye pattern is a system level concern which components allow the data path layout connector with also impact. TPS25830 has a market-proven good eye diagram performance to ease the challenge of passing the eye diagram.
TPS25830 also has a very robust short-to-battery protection and IEC ESD protection of our VBUS, data lines, and CCPs. This helps to save the [INAUDIBLE] cost and size.
For media hub, efficiency and size becomes critical. As the board for media hub becomes smaller, the number or ports becomes larger and the power delivered from each USB port becomes higher. In this case, TPS25830 is an all-in-one device with DC/DC USB controller and protection in 5X5 package for a small-size application.
And the port is also designed for good efficiency at both 400K hertz and 2 megahertz. Moreover, the integrated DC/DC in TPS25830 is designed for 3.5A, which has additional 500A to power other circuit outside of USB. For example, an LDO for host or hub IC. In this way, the system can get [INAUDIBLE] of a high-voltage LDO with poor efficiency to convert battery rebooting to 3.3 volt. Instead, it will use the 5-volt from TPS25830 to power a low-voltage LDO for 3.3 volt to improve the efficiency of the total solution.
For rear seat charger, normally, it's a charging-only application. So TPS25831 with DCP mode is the solution here. This is also the key difference between 25830 and 25831-- is that one supports charging plus data communication, and the other supports charging only.
Similarly to media hub, the rear seat charger also cares about efficiency and size due to the increase of power density. The high power density introduced thermal issue to these modules, so TPS25831 not only has a good efficiency at 400K hertz, which normally used in rear seat charger, but also integrates an NTC function to lower the charging advertisement when the temperature hits these flash holes set by the NTC pin. This NTC function enables intelligent thermal management before the device goes completely thermal shut down when [INAUDIBLE] which is 165 degrees Celsius.
For local Type A port, short-to-battery protection could be a concern, as in real world, a tightly connector with lightning cable connected could accidentally jump into the 12-volt cigarette lighter port and cause damage. In this case, both TPS25830 and TPS25831 have integrated the short-to-battery protection for all pings. So no matter it's charging with data commutation or charging-only application, the devices can protect for it from short-to-battery protection.
TPS25830 and TPS25831 are very strong devices with many functions. So to know more about the devices, please contact us for more information, and please go to our home page for Automotive USB for more information. Thank you for listening.

Details

Date:
September 19, 2018

Start with a review of USB-A, USB-C, and USB-PD. Briefly covering he differences, as well as what they are and are not. This is followed by more detailed review of common USB-C applications with the attendant challenges and solutions.